Deep brain stimulation can be useful for treating a variety of conditions including, for example, Parkinson's disease, dystonia, essential tremor, chronic pain, Huntington's Disease, levodopa-induced dyskinesias and rigidity, bradykinesia, epilepsy and seizures, eating disorders, and mood disorders. Typically, a lead with a stimulating electrode at or near a tip of the lead provides the stimulation to target neurons in the brain. Magnetic resonance imaging (MRI) or computerized tomography (CT) scans can provide a starting point for determining where the stimulating electrode should be positioned to provide the desired stimulus to the target neurons.
Upon insertion, current is introduced along the length of the lead to stimulate target neurons in the brain. This stimulation is provided by electrodes, typically in the form of rings, disposed on the lead. The current projects from each electrode similarly and in all directions at any given length along the axis of the lead. Because of the shape of the electrodes, radial selectivity of the current is minimal. This results in the unwanted stimulation of neighboring neural tissue, undesired side effects and an increased duration of time for the proper therapeutic effect to be obtained.